Author: Lin, F.
Paper Title Page
THP079 Recent RHIC-motivated Polarized Proton Developments in the Brookhaven AGS 2282
 
  • V. Schoefer, L. A. Ahrens, M. Bai, S. Binello, M. Blaskiewicz, K.A. Brown, C.J. Gardner, J.W. Glenn, H. Huang, F. Lin, W.W. MacKay, J. Morris, S. Nemesure, T. Roser, S. Tepikian, N. Tsoupas, K. Yip, A. Zelenski, K. Zeno
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The RHIC polarized proton physics program requires high luminosity and high polarization which depends directly on the intensity, emittances and polarization delivered to RHIC by the injector chain. In the AGS, two partial snakes create gaps in the realized spin-tune around the integers which allows an accelerating beam with sufficiently small vertical emittance and near-integer vertical tune to avoid the imperfection and vertical intrinsic resonances. The same strategy strengthens the many (82) weak horizontal intrinsic resonances crossed during AGS acceleration. A system speeding up these resonance crossings – the AGS JumpQuad system: 82 tiny (0.04) fast (100usec) betatron tune shifts – has been commissioned and evolved during RHIC Runs 09, 10, and 11. Subtle properties of the AGS geometry and lattice, magnified into relevance by the high vertical tune can result in polarization-damaging emittance growth when combined with the Jump Quad gymnastics. Orbit stability is critical. Some aspects of the JumpQuad system, of this commissioning effort and related developments will be described.
 
 
THP189 Low Horizontal Beta Function in Long Straights of the NSLS-II Lattice 2471
 
  • F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886
The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of maintaining three long straights with large horizontal beta function while providing the other 12 long straights with smaller horizontal beta function to optimize the brightness of insertion devices. Our study considers the possible linear lattice solutions as well as characterizing the nonlinear dynamics. Results are reported on optimizations of dynamic aperture required for good injection efficiency and adequate Touschek lifetime.
 
 
THP190 Additional Quadrupoles at Center of Long Straights in the NSLS-II Lattice 2474
 
  • F. Lin, J. Bengtsson, W. Guo, S. Krinsky, Y. Li, L. Yang
    BNL, Upton, Long Island, New York, USA
 
  Funding: Work supported by U.S. DOE, Contract No. DE-AC02-98CH10886
The NSLS-II storage ring lattice is comprised of 30 DBA cells arranged in 15 superperiods. There are 15 long straight sections (9.3m) for injection, RF and insertion devices and 15 shorter straights (6.6m) for insertion devices. In the baseline lattice, the short straights have small horizontal and vertical beta functions but the long straights have large horizontal beta function optimized for injection. In this note, we explore the possibility of installing additional quadrupoles at the center of selected long straight sections in order to provide two low-beta source locations for undulators. The required modification to the linear lattice is discussed as well as the preservation of adequate dynamic aperture required for good injection efficiency and adequate Touschek lifetime.